Needle tip and seat for a choke valve

ABSTRACT

Embodiments of the present disclosure relate to a choke valve that includes a choke body, a choke trim disposed in the choke body, where the choke trim is configured to adjust a cross-sectional area of a flow path in the choke body to adjust a fluid flow through the choke valve, a needle of the choke trim disposed in the flow path of the fluid flow, where the needle includes a first portion having a superhard material, a seat of the choke trim, where the needle is configured to move along an axis extending through an opening of the seat to adjust the fluid flow through the choke valve.

BACKGROUND

This section is intended to introduce the reader to various aspects ofart that may be related to various aspects of the present disclosure,which are described and/or claimed below. This discussion is believed tobe helpful in providing the reader with background information tofacilitate a better understanding of the various aspects of the presentdisclosure. Accordingly, it should be understood that these statementsare to be read in this light, and not as admissions of prior art.

In certain fluid-handling systems, such as mineral extraction systems, avariety of flow control devices are used to control a flow rate, apressure, and other parameters of fluid flow. For example, in mineralextraction systems, choke valves may be utilized to regulate the flow ofproduction fluid (e.g., oil, gas, and water) from a well. An actuatordrives a movable valve member over an opening through which the fluidflows. Shifting the position of the movable valve member relative to theopening adjusts the flow rate of the fluid through the opening.Unfortunately movable valve members may be subject to relatively highpressure drop environments, abrasive media entrained in the fluid,and/or fluid flow cavitation, which may lead to wear, erosion, and otherdegradation.

BRIEF DESCRIPTION OF THE DRAWINGS

Various features, aspects, and advantages of the present disclosure willbecome better understood when the following detailed description is readwith reference to the accompanying figures in which like charactersrepresent like parts throughout the figures, wherein:

FIG. 1 is a schematic of a fluid-handling system including a chokevalve, in accordance with an embodiment of the present disclosure;

FIG. 2 is a cross-sectional side view of an embodiment of a choke trimof the choke valve of FIG. 1, in accordance with an embodiment of thepresent disclosure;

FIG. 3 is a cross-sectional side view of an embodiment of the choke trimof the choke valve of FIG. 1, in accordance with an embodiment of thepresent disclosure;

FIG. 4 is a perspective view of an embodiment of the choke trim of thechoke valve of FIG. 3, in accordance with an embodiment of the presentdisclosure;

FIG. 5 is a cross-sectional side view of an embodiment of the choke trimof the choke valve of FIG. 1, in accordance with an embodiment of thepresent disclosure; and

FIG. 6 is a block diagram of an embodiment of a process for assemblingthe choke trim of the choke valve of FIGS. 1-5, in accordance with anembodiment of the present disclosure.

DETAILED DESCRIPTION OF SPECIFIC EMBODIMENTS

One or more specific embodiments of the present disclosure will bedescribed below. These described embodiments are only exemplary of thepresent disclosure. Additionally, in an effort to provide a concisedescription of these exemplary embodiments, all features of an actualimplementation may not be described in the specification. It should beappreciated that in the development of any such actual implementation,as in any engineering or design project, numerousimplementation-specific decisions must be made to achieve thedevelopers' specific goals, such as compliance with system-related andbusiness-related constraints, which may vary from one implementation toanother. Moreover, it should be appreciated that such a developmenteffort might be complex and time consuming, but would nevertheless be aroutine undertaking of design, fabrication, and manufacture for those ofordinary skill having the benefit of this disclosure.

When introducing elements of various embodiments, the articles “a,”“an,” “the,” “said,” and the like, are intended to mean that there areone or more of the elements. The terms “comprising,” “including,”“having,” and the like are intended to be inclusive and mean that theremay be additional elements other than the listed elements. The use of“top,” “bottom,” “above,” “below,” and variations of these terms is madefor convenience, but does not require any particular orientation of thecomponents relative to some fixed reference, such as the direction ofgravity. The term “fluid” encompasses liquids, gases, vapors, andcombinations thereof.

Embodiments of the present disclosure are directed toward fluid-handlingsystems, such as a fluid-handling system for a mineral extraction system(e.g., drilling systems, hydraulic fracturing systems, among others).Fluid-handling systems may include a choke valve that includes a chokebody and a choke trim disposed within the choke body. The choke trim mayinclude a needle configured to move relative to an opening in the chokevalve to adjust a fluid flow through the choke valve. Movement of theneedle may be limited by a seat of the choke trim, and when the needlecontacts the seat, the opening may be completely covered, such that nofluid flows through the choke valve. The choke trim may also include astem coupled to an actuator that may be configured to move the needlewith respect to the opening and/or the seat, thereby adjusting across-sectional area of a fluid flow path extending through the chokebody to adjust the fluid flow. In some cases, the needle and/or the seatmay incur degradation (e.g., erosion) and/or wear as a result of highpressure drops experienced at a tip portion of the needle. Traditionalneedle and seat choke trims may include a tungsten carbide material,which may be vulnerable to degradation, thereby leading to replacementof the choke trim after a relatively short duration.

Accordingly, it may be desirable to utilize a needle and seat choke trimthat includes at least a tip portion having a superhard material (e.g.,a diamond-based material, polycrystalline cubic boron nitride, amaterial with a hardness value exceeding approximately (e.g., within1%-10%) 20 gigaPascals (GPa) based on the Vickers hardness test, and/ora material with a hardness value exceeding approximately (e.g., within1%-10%) 4500 Hardness Brinell (HB) on the Brinell scale). However, dueto manufacturing tolerances (e.g., size limitations) and/or costconstraints, a superhard material may not be included in the entirechoke trim (e.g., the choke trim is not fully constructed of thesuperhard material). Therefore, it is now recognized that it may bedesirable to include a superhard material in a tip portion of the needleand/or a seating surface of the seat of the choke trim.

As used herein, a superhard material may include a diamond-basedmaterial (e.g., silicon centered diamond, polycrystalline diamond,and/or another material that includes diamond), a polycrystalline cubicboron nitride, a material that includes a hardness value exceeding 20GPa based on the Vickers hardness test, and/or a material that includesa hardness value exceeding 4500 HB on the Brinell scale. As anon-limiting example, the superhard material may include polycrystallinediamond compacts, polycrystalline diamond discs, and/or thermally stableproducts made commercially available by Shannon-Abrasives of Shannon,Ireland. In any case, the tip portion of the needle may include asuperhard material that may enable the needle to better withstand highpressure drops experienced within the choke valve body when compared totraditional choke needles. Additionally, in some embodiments, at least aportion of a surface of the seat in which the needle contacts alsoincludes the superhard material to resist wear resulting from contactbetween the needle and the surface. Accordingly, a durability of thefluid-handling system may be enhanced.

To help illustrate the manner in which the present embodiments may beused in a system, FIG. 1 illustrates an embodiment of a fluid-handlingsystem 10. The fluid-handling system 10 may be part of anenergy-acquisition or processing system, e.g., a hydrocarbon-productionor processing system, such as a subsea or surface oil or gas well. Insome embodiments, the fluid-handling system 10 may be a gas-upliftsystem, a water-injection system, a water/steam/chemicals injectionsystem, or other system for conveying fluids. The fluid-handling system10 includes a fluid source 12, a choke valve 14, and a fluid destination16. The fluid source 12 may include a variety of fluid sources, such asan oil or natural gas well. The fluid source 12 may supply a variety offluids, such as air, natural gas, oil, water (steam or liquid), orcombinations thereof. The fluid arriving from the source 12 may be atrelatively high pressures, e.g., pressures greater than 500 psi, 1000psi, 5000 psi, 10,000 psi, 15,000 psi, 20,000 psi, 25,000 psi, or 30,000psi. Additionally, the pressure of the fluid arriving from the source 12may be higher than the pressure at the fluid destination 16.

The choke valve 14 includes an inlet 18, a choke body 20 (e.g., aproduction choke body and/or a universal choke body), a choke trim 22disposed within the choke body 20, an actuator 24, and a fluid outlet26. The actuator 24 may modulate flow between the inlet 18 and theoutlet 26 by adjusting the position of the choke trim 22 or a componentof the choke trim 22 (e.g., a stem coupled to a needle) relative to asecond component of the choke trim 22 (e.g., a seat of the choke trim22) and/or the choke body 20. The component of the choke trim 22 (e.g.,a needle) may adjust a cross-sectional area of a flow path of the fluidthrough the choke body, thereby adjusting the flow between the inlet 18and the outlet 26. For example, the actuator 24 may be a manual actuator(e.g., a wheel), an electro-mechanical actuator (e.g., an electric driveor motor), a hydraulic actuator (e.g., a fluid driven actuator), apneumatic actuator (e.g., a pressure drive actuator), or other suitabletype of actuator. To adjust the position of the choke trim 22 or acomponent of the choke trim 22 (e.g., a stem and/or a needle), theactuator 24 may exert a translational force on a shaft 28 coupled to theactuator 24 and the choke trim 22 or a component of the choke trim 22.

As mentioned above, the choke trim 22 may include a needle 30 and a seat32. In some embodiments, one or more springs 34 may be disposed betweenthe needle 30 and the shaft 28 such that a biasing force is applied tothe needle 30. The spring 34 may be any suitable biasing member, such asa series (e.g., stack) of tapered annular washers (e.g., Bellvillewashers), one or more coil springs (e.g., stacked or concentricsprings), an elastic material (e.g., a ring made of rubber orelastomer), or any combination thereof. During movement of the choketrim 22 to a closed position in which the needle 30 is fully seatedagainst the seat 32 (e.g., an annular seat), the spring 34 may reduce aload applied by the needle 30 to the seat 32 and/or reduce a loadapplied by the shaft 28 to the needle 30, thereby reducing wear oncertain components of the choke valve 14. In other embodiments, thechoke valve 14 may not include the springs 34.

As will be appreciated, additional equipment 36 may be coupled to thefluid-handling system 10 (e.g., the choke valve 14 and/or the actuator24). For example, the equipment 36 coupled to the fluid-handling system10 may including drilling equipment, fracking equipment, productionequipment, and/or other suitable equipment. In certain embodiments, theadditional equipment 36 may include a controller 38 configured toregulate operation of the actuator 24 based on the type of additionalequipment 36 being used, based on operating conditions of thefluid-handling system 10 (e.g., a fluid flow rate through the chokevalve 14, a pressure of the fluid flow within the choke body 20), and/oranother suitable parameter of the fluid-handling system 10. While thepresent discussion is focused on utilizing the choke valve 14 with thefluid-handling system 10, it should be recognized that the disclosedembodiments of the choke valve 14 may be included in other suitablesystems. For example, the choke valve 14 having a needle and/or a seatwith a superhard material may be utilized in hydraulic fracturingsystems, which may expose the choke valve 14 to abrasive fluids. Assuch, utilizing the embodiments of the choke valve 14 with such systemsmay enhance an operating life of the choke valve 14.

As discussed above, the choke trim 22 may experience relatively highpressure drops, thereby leading to degradation (e.g., wear) oncomponents of the choke trim 22 (e.g., the needle 30). As shown in FIG.2, the needle 30 may include a portion 50 (e.g., a first annularportion) that includes a first material 52 (e.g., a superhard material).The material 52 utilized in the portion 50 may include a superhardmaterial (e.g., a diamond-based material, polycrystalline cubic boronnitride, a material with a hardness value exceeding approximately (e.g.,within 1% and 10%) 20 GPa based on the Vickers hardness test, and/or amaterial with a hardness value exceeding approximately (e.g., within 1%and 10%) 4500 HB on the Brinell scale). In some embodiments, thesuperhard material may include an amount of diamond-based material(e.g., polycrystalline diamond) between 25% and 100%, between 50% and95%, between 65% and 96%, or between 75% and 90% of a total weight ofthe material 52. Further, the portion 50 may include one or moresegments to accommodate manufacturing tolerances that may limit the sizeof commercially available components that include superhard materials.However, it may be desirable to form a needle having a superhardmaterial and configured to have generally the same size as a traditionalneedle. Accordingly, the enhanced needle 30 (e.g., having a superhardportion) may be installed in existing fluid-handling systems 10 withoutmodification. In some embodiments, multiple segments (e.g., 2, 3, 4, 5,or more) containing the superhard material may be used to form theenhanced needle 30 that is generally the same size as a traditionalneedle.

Additionally, the portion 50 may be coupled to a stem 54 (e.g., the stem54 may be disposed upstream or downstream of the portion 50 relative tothe flow path of fluid through the choke body 20) of the needle 30,which may include a second material 56 (e.g., a non-superhard material).In certain embodiments, the stem 54 may include a non-superhard materialutilized in existing fluid-handling systems 10 such as a nickel alloy,tungsten carbide, steel (e.g., stainless steel), or another suitablematerial. Further, the needle 30 may include a portion 58 (e.g., asecond annular portion) that includes a third material 60 (e.g., anon-superhard material) and couples the portion 50 to the stem 54. Forexample, the third material 60 may include nickel alloy, tungstencarbide, steel (e.g., stainless steel), or another suitable material. Inother embodiments, the third material 60 may include a material that hasa hardness between 5% and 99%, between 25% and 95%, or between 75% and90% of a hardness of the material 52 of the portion 50. In any case, theportion 50 is disposed around a base 59 of the portion 58 to couple theportion 50 to the stem 54.

In some embodiments, seals 61 may be disposed between the portion 50,the portion 58 and/or the stem 54. As used herein, the seals 61 mayinclude a washer, an “O”-ring, another sealing device that includes ametallic material and/or an elastomeric material, and/or a combinationthereof. In certain embodiments, the seals 61 may include the firstmaterial 52, the second material 56, and/or another suitable material(e.g., metal and/or elastomeric material).

In some embodiments, the base 59 of the portion 58 is disposed in anopening 62 of the stem 54 and secures the portion 58 to the stem 54. Forexample, the base 59 may be secured into the opening 62 to blockmovement of the portion 58 (and thus the portion 50) with respect to thestem 54. In some embodiments, the base 59 is secured in the opening 62via a shrink fit. As such, a temperature of the stem 54 may be increasedto increase a size of the opening 62, such that the base 59 can bedisposed within the opening 62. Subsequently, the temperature of thestem 54 is reduced after disposing the base 59 in the opening 62, suchthat a size of the opening 62 reduces and the opening 62 contractsaround the base 59, such that movement of the portion 58 (and thus theportion 50) is blocked relative to the opening 62. In other embodiments,the base 59 may be secured in the opening 62 using threads on the base59 that engage with corresponding threads in the opening 62 (see, e.g.,FIG. 5). In still further embodiments, the base 59 may be secured intothe opening 62 using any other suitable technique (e.g., brazing,welding, adhesives, among other techniques).

As shown in the illustrated embodiment of FIG. 2, the needle 30 may movealong an axis 64, such that the needle 30 adjusts a size of an opening66 extending through the seat 32. For example, a flow of fluid may besubstantially blocked when the needle 30 contacts a surface 67 of theseat 32 because the opening 66 may be substantially sealed by the needle30. Conversely, the flow of fluid increases as the needle 30 moves alongthe axis 64 away from the seat 32 (e.g., as shown by arrow 68). In somecases, contact between the needle 30 and the surface 67 of the seat 32may degrade and/or wear the seat 32 over time. Thus, in someembodiments, the seat 32 may include a portion 70 (e.g., a third annularportion) that has a superhard material to reduce degradation and/or wearcaused by contact between the surface 67 and the needle 30. In someembodiments, the portion 70 may be an annular disc that is coupled to abody portion 72 (e.g., an annular body portion) of the seat 32. In someembodiments, the portion 70 is secured within the body portion 72 viashrink fitting. In other embodiments, the portion 70 may be coupled tothe body portion 72 through brazing, welding, adhesives, threads, oranother suitable technique.

The portion 50 of the needle 30 may include a tapered surface 74 (e.g.,a first annular tapered surface) that is configured to facilitate a sealbetween the needle 30 and the seat 32. Additionally, the portion 70 ofthe seat 32 may include a corresponding tapered surface 76 (e.g., asecond annular tapered surface) that engages with the tapered surface 74to form the seal. In some embodiments, the tapered surface 74 and/or thetapered surface 76 form an angle 78 with the axis 64 along which theneedle 30 moves. For example, the angle 78 may be between 1 and 45degrees, between 2 and 25 degrees, or between 5 and 10 degrees. In anycase, the angle 78 may facilitate a seal between the needle 30 and theseat 32 when the needle 30 is disposed within the opening 66 of the seat32.

Further, the seat 32 may include a portion 80 (e.g., a fourth annularportion) that is also secured within the body portion 72 of the seat 32.The portion 80 may include a non-superhard material that is differentfrom, or the same as, a material of the body portion 72. As anon-limiting example, in some embodiments, the portion 80 includestungsten carbide and the body portion 72 includes stainless steel. Inother embodiments, the portion 80 and the body portion 72 each includetungsten carbide and/or stainless steel. Including the portion 80 in theseat 32 may enhance a robustness of the seat 32 because the portion 80is exposed to high temperatures and high pressure drops that degradeand/or wear the seat 32. Thus, including the portion 80 that has arobust material may increase an operating life of the seat 32, therebyreducing operating costs and maintenance times associated with of thefluid handling assembly 10.

FIG. 3 is a cross-sectional side view of an embodiment of the choke trim22, where the needle 30 includes a portion 100 (e.g., a fifth annularportion) in addition to the portions 50 and 58. The portion 100 mayinclude a material 102 (e.g., a non-superhard material) that is the sameas, or different from, the portions 50 and/or 58. In some embodiments,the material 102 may include tungsten carbide, stainless steel, anothersuitable material, or a combination thereof. In other embodiments, thematerial 102 may include a nanoparticle coating (e.g., diamondnanoparticle coating, gold nanoparticle coating, silver nanoparticlecoating, titanium nanoparticle coating, or a combination thereof) thatis applied to tungsten carbide, stainless steel, another suitablematerial, or a combination thereof. In still further embodiments, thematerial 102 may include a treated surface (e.g., a heat treatedsurface) and/or any other suitable material. Further, the material 102may include a hardness that is between 5% and 99%, between 25% and 95%,or between 75% and 90% of a hardness of the material 52.

In any case, the portion 100 may be utilized to further enhance anoperating life of the needle 30. For example, the material 102 mayinclude a hardness that is greater than the material 60 of the portion58. As shown in the illustrated embodiment of FIG. 3, the portion 100 ispositioned adjacent to the portion 50, which contacts the seat 32 andultimately forms the seal between the needle 30 and the seat 32.Accordingly, the portion 100 may also experience relatively hightemperatures and high pressure drops. Further, the portion 100 may beexposed to fluids that have relatively high concentrations of particles,thereby causing degradation and/or wear via abrasion. Accordingly, theportion 100 may provide a harder, more robust material in an area thatis exposed to relatively harsh conditions to enhance an operating lifeof the needle 30. For example, the portions 58 and 100 may be exposed tofluid after the portion 50. Thus, while the portion 50 at leastpartially blocks the portions 58 and 100 from the harsh conditions inthe fluid handling assembly 10, the portions 58 and 100 may include amore robust material that may better withstand the high particleconcentrations, high temperatures, and/or high pressure drops. Thelonger the portions 58 and 100 withstand any abrasion caused by thefluid, the longer the needle 30 may sufficiently provide a seal in theopening 66 without maintenance and/or repair.

As shown in the illustrated embodiment of FIG. 3, the portion 100 mayinclude a thickness 104 that is less than a thickness 106 of the portion50. In some embodiments, the thickness 104 of the portion 100 is between10% and 50%, between 15% and 40%, or between 20% and 35% of thethickness 106 of the portion 50. In other embodiments, the thicknesses104 and 106 may be substantially equal to (e.g., within 10%, within 5%,or within 1% of) one another. Additionally, in some embodiments, theportion 100 includes a tapered surface 108. The tapered surface 108 mayfacilitate insertion of the needle 30 into the opening 66 of the seat 32and enable contact between the portion 50 and the surface 67 of the seat32. Accordingly, the portion 50, which may include a more robustmaterial than the portion 100, contacts the surface 67 of the seat 32and reduces wear on the needle 30.

FIG. 4 is an exploded perspective view of the choke trim 22 of FIG. 3.As shown in the illustrated embodiment of FIG. 4, the portions 50 and100 are disposed around the base 59 of the portion 58 to form the needle30. The base 59 is configured to be inserted into the opening 62 of thestem 54 and secured to the stem 54, such that the needle 30 and the stem54 do not move relative to one another.

As discussed above, the actuator 24 is configured to move the stem 54(e.g., via the shaft 28) along the axis 64, such that the needle 30moves along the axis 64 toward and away from the seat 32. As shown inthe illustrated embodiment of FIG. 4, the seat 32 includes the opening66 that is configured to receive the needle 30 (e.g., the portions 50,58, and 100). Further, the portions 70 and 80 of the seat 32 are securedwithin the body portion 72 of the seat 32 to form the seating surface 67(e.g., a surface in which the needle contacts). The body portion 72 ofthe seat 32 may include threads 130 that engage with correspondingthreads of the choke body 20 of the choke valve 14. Accordingly, theseat 32 may be secured within the choke body 20, such that the needle 30moves along the axis 64 with respect to the choke body 20 and the seat32.

FIG. 5 is a cross-sectional view of an embodiment of the choke trim 22,where the body portion 59 is coupled to the stem 54 via threads 140 ofthe body portion 59 that engage corresponding threads 141 of the stem54. As such, the body portion 59 is secured into the stem 54 via thethreads 140 and 141. Utilizing the threads 140 and 141 may enable thebody portion 59 to be secured within the stem 54 without undergoing ashrink fit procedure, which may facilitate assembly of the choke trim22.

Additionally, as shown in the illustrated embodiment of FIG. 5, aposition of the portion 100 and the portion 50 may be reversed whencompared to the embodiments of FIGS. 3 and 4. Thus, the portion 50 maystill engage one or more of the portions 70 and/or 80 of the seat 32,while the portion 100 may be exposed to fluid (e.g., abrasive fluid)before the portion 50 (e.g., the portion 100 is positioned upstream ofthe portion 50 with respect to a flow of the fluid through the chokevalve 14). As discussed above, the portion 100 may include a material102 (e.g., a non-superhard material) that is the same as, or differentfrom, the portions 50 and/or 58. In some embodiments, the material 102may include tungsten carbide, stainless steel, another suitablematerial, or a combination thereof. In other embodiments, the material102 may include a nanoparticle coating (e.g., diamond nanoparticlecoating, gold nanoparticle coating, silver nanoparticle coating,titanium nanoparticle coating, or a combination thereof) that is appliedto tungsten carbide, stainless steel, another suitable material, or acombination thereof. In still further embodiments, the material 102 mayinclude a treated surface (e.g., a heat treated surface) and/or anyother suitable material. Further, the material 102 may include ahardness that is between 5% and 99%, between 25% and 95%, or between 75%and 90% of a hardness of the material 52. As set forth above, theportion 50 may include the material 52, which may be a superhardmaterial.

In some embodiments, the portion 50 may include a first segment 142configured to engage a first surface 143 of the portion 70 disposed inthe body portion 72 of the seat 32. Further, the portion 50 includes asecond segment 144 that conforms to and/or engages with a second surface145 of the body portion 72. However, in other embodiments, the portion50 may include a single segment or more than two segments (e.g., taperedsurfaces having different angles with respect to the axis 64).

FIG. 6 is a block diagram of a process 150 that may be used tomanufacture one or more of the previously discussed embodiments of thechoke trim 22. For example, at block 152 a first plurality of segments(e.g., the portion 50, the portion 58, and/or the portion 100) may becoupled to one another to form the needle 30 of the choke trim 22. Asdiscussed above, one or more of the plurality of segments (e.g., theportion 50, the portion 58, and/or the portion 100) may include thematerial 52 (e.g., a superhard material). At block 154, a secondplurality of segments (e.g., the portion 70, the body portion 72, and/orthe portion 80) may be coupled to one another to form the seat 32. Forexample, the portion 70 and the portion 80 are disposed within theopening 66 of the body portion 72 and secured in the body portion 72(e.g., via shrink fitting, welding, brazing, etc.) to form the surface67 in which the needle 30 contacts to form a seal. Additionally, atblock 156, the stem 54 may be coupled to the body 59 of the portion 58,such that the needle 30 is configured to move along the axis 64 (e.g.,via the actuator 24) relative to the seat 32. In some embodiments, thestem 54 may a non-superhard material, such as tungsten carbide,stainless steel, or another suitable material. The body 59 of theportion 58 may be secured within the opening 62 of the stem 54 viashrink fitting, threads, brazing, welding, and/or any other suitabletechnique. Further, at block 158, the choke trim 22 may be disposed inthe choke body 20 such that the choke trim 22 may be utilized to adjusta cross-sectional area of a flow path of the fluid flowing through thechoke valve 14.

While the present disclosure may be susceptible to various modificationsand alternative forms, specific embodiments have been shown by way ofexample in the drawings and have been described in detail herein.However, it should be understood that the present disclosure is notintended to be limited to the particular forms disclosed. Rather, thepresent disclosure is to cover all modifications, equivalents, andalternatives falling within the spirit and scope of the disclosure asdefined by the following appended claims.

The invention claimed is:
 1. A choke valve, comprising: a choke body; achoke trim disposed in the choke body, wherein the choke trim isconfigured to adjust a cross-sectional area of a flow path in the chokebody to adjust a fluid flow through the choke valve; a needle of thechoke trim disposed in the flow path of the fluid flow, wherein theneedle comprises a first annular portion having a superhard material anda second annular portion, the first annular portion and the secondannular portion are disposed at different axial positions of the needle,the first annular portion and the second annular portion are configuredto receive a base of a third portion of the needle to couple the firstannular portion and the second annular portion to a stem of the choketrim, the third portion comprises a tip, the first annular portion andthe second annular portion are configured to be positioned between thetip and the stem of the choke trim, and the needle comprises a taperedannular surface extending at least partially along a first exterior ofthe first annular portion and at least partially along a second exteriorof the second annular portion; and a seat of the choke trim, wherein theneedle is configured to move along an axis extending through an openingof the seat to adjust the fluid flow through the choke valve.
 2. Thechoke valve of claim 1, wherein the seat comprises a fourth portionhaving the superhard material, and a first axial length of the firstannular portion having the superhard material is greater than a secondaxial length of the fourth portion having the superhard material.
 3. Thechoke valve of claim 1, wherein the second annular portion comprises asecond material different than the superhard material, the tip of thethird portion comprises a third material different than the superhardmaterial and the second material, the superhard material is harder thanthe second material, and the second material is harder than the thirdmaterial.
 4. The choke valve of claim 3, wherein the superhard materialcomprises polycrystalline diamond, and the second material comprisestungsten carbide.
 5. The choke valve of claim 4, wherein the tungstencarbide is coated with a diamond nanoparticle coating.
 6. The chokevalve of claim 1, wherein the first annular portion is made entirely ofthe superhard material.
 7. The choke valve of claim 1, wherein thesuperhard material comprises polycrystalline diamond.
 8. The choke valveof claim 7, wherein the superhard material comprises between 65% and 96%polycrystalline diamond by weight.
 9. The choke valve of claim 1,wherein the tapered annular surface extends at least partially along athird exterior of the tip of the of the third portion, and the taperedannular surface is continuous at a first transition between the firstand second annular portions and at a second transition between the tipand the first or second annular portion.
 10. The choke valve of claim 1,wherein an angle of the tapered annular surface is constant.
 11. Thechoke valve of claim 1, wherein the first annular portion has a firstaxial length, the second annular portion has a second axial length, andthe tip has a third axial length, wherein the third axial length isgreater than each of the first and second axial lengths.
 12. A choketrim for a choke valve, comprising: a needle disposed in a flow path offluid flow through the choke valve, wherein the needle comprises a firstannular portion having a superhard material and a second annular portionhaving a second material, the superhard material is harder than thesecond material, the first annular portion and the second annularportion are disposed at different axial positions of the needle, thefirst annular portion and the second annular portion are configured toreceive a base of a third portion of the needle to couple the firstannular portion and the second annular portion to a stem of the choketrim, the third portion comprises a tip having a third material, thesecond material is harder than the third material, and the first annularportion and the second annular portion are configured to be positionedbetween the tip and the stem of the choke trim; and a seat, wherein theneedle is configured to move along an axis extending through an openingof the seat to adjust the fluid flow through the choke valve.
 13. Thechoke trim of claim 12, wherein the first annular portion is madeentirely of the superhard material.
 14. The choke trim of claim 13,wherein the superhard material comprises at least 65% polycrystallinediamond by weight.
 15. The choke trim of claim 12, wherein the needlecomprises a tapered annular surface extending at least partially along afirst exterior of the first annular portion and a second exterior of thesecond annular portion.
 16. The choke trim of claim 15, wherein thetapered annular surface extends at least partially along a thirdexterior of the tip of the of the third portion, and the tapered annularsurface is continuous at a first transition between the first and secondannular portions and at a second transition between the tip and thefirst or second annular portion.
 17. A method, comprising: coupling afirst plurality of segments to one another to form a needle of a chokevalve, wherein a first segment of the first plurality of segmentscomprises a superhard material, a second segment of the first pluralityof segments is disposed at a different axial position of the needle thanthe first segment, the first segment and the second segment are annularand are configured to receive a base of a third segment of the firstplurality of segments to couple the first segment and the second segmentto a stem of a choke trim of the choke valve, the third segmentcomprises a tip, the first segment and the second segment are configuredto be positioned between the tip and the stem of the choke trim, thesecond segment comprises a second material different than the superhardmaterial, the tip of the third segment comprises a third materialdifferent than the superhard material and the second material, thesuperhard material is harder than the second material, and the secondmaterial is harder than the third material; coupling a second pluralityof segments to one another to form a seat of the choke valve, whereinthe needle and the seat form the choke trim of the choke valve; couplingthe third segment of the first plurality of segments to the stem toenable movement of the needle relative to the seat; and disposing thechoke trim in a choke body of the choke valve, such that the choke trimis configured to adjust a cross-sectional area of a flow path of a fluidflowing through the choke valve.
 18. The method of claim 17, whereincoupling the third segment of the first plurality of segments to thestem to enable movement of the needle relative to the seat comprisesshrink fitting the third segment into an opening of the stem, whereinthe third segment has a central bore extending lengthwise along thethird segment from the tip to the opening of the stem.
 19. A chokevalve, comprising: a choke body; a choke trim disposed in the chokebody, wherein the choke trim is configured to adjust a cross-sectionalarea of a flow path in the choke body to adjust a fluid flow through thechoke valve; a needle of the choke trim disposed in the flow path of thefluid flow, wherein the needle comprises a first annular portion havinga superhard material and a second annular portion, the first annularportion and the second annular portion are disposed at different axialpositions of the needle, the first annular portion and the secondannular portion are configured to receive a base of a third portion ofthe needle to couple the first annular portion and the second annularportion to a stem of the choke trim, the third portion comprises a tip,the first annular portion and the second annular portion are configuredto be positioned between the tip and the stem of the choke trim, thesecond annular portion comprises a second material different than thesuperhard material, the tip of the third portion comprises a thirdmaterial different than the superhard material and the second material,the superhard material is harder than the second material, and thesecond material is harder than the third material; and a seat of thechoke trim, wherein the needle is configured to move along an axisextending through an opening of the seat to adjust the fluid flowthrough the choke valve.